Durable pen



Patented Dec. 21,

UNITED STATES PATENT OFFICE.

' mm YonnzU, or TOKYO nu, AND EITARO nnno, on Tokyo, JAPAN.

DURABLE PEN.

no Drawing. 1 Application filed Apri1 2 This invention relates to a pen made with a metal of the iron roup, such as nickel,

iron or alloyof'nicke and iron, containing from 8 to 30% of chromium, and the object 10 tic of resisting wear nomatter what its hardness is. Forinstance, if the alloy above described is turned in a lathe, the bit if made of common tool steel of greater hardness will rapidlyfwearoft and become utterly useless very soon. Comparing this with the. case. in which common carbon steel is turned, there is a marked difference in the um, though a little less in, degree.

In this invention, advantage is taken of the above property, together with the known corrosionresisting'property of high chromium alloys, in making durable pens.

These properties increase in degree ac- 3, 1924. Serial in). 708,567.

cording to increase of proportion of chromium, but too much chromium makes the manufacture of pens difiicult as the alloy becomes less malleable. The proportion of chromium should therefore be limited to from 8 to In manufacturing pens with this alloy, the addition of a small proportion, as required, of vanadium, mangaynese, aluminium and other metals will make the manufacture easier and does not decrease in the least the durability of the pens produced. y

loy of chromium 20%, nickel 5%, and vanadium 4%, the remainder being iron, is twenty times longer than that of steel pens hitherto in use of greater hardness. We 'claim Y f 1. A writing pen made with an alloy of a metal of the iron group containing 8 to 30% of chromium and 1' to 10% of vanadium. I

2. A writing pen made with an alloy of iron and nickel containing 8 to- 30% of chromium and. 1 to 10% of vanadium.

In testimony whereof we havesigned our names to this specification.

MASAAKI YONEZU. v

EITARO ENDO.

The normal life of pens made of an al 

